U.S. patent application number 16/891804 was filed with the patent office on 2020-12-10 for inter-radio access technology interference cancellation.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Amit Bar-Or Tillinger, Gideon Shlomo Kutz, Shay Landis, Michael Levitsky, Assaf Touboul.
Application Number | 20200389771 16/891804 |
Document ID | / |
Family ID | 1000004883081 |
Filed Date | 2020-12-10 |
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United States Patent
Application |
20200389771 |
Kind Code |
A1 |
Landis; Shay ; et
al. |
December 10, 2020 |
INTER-RADIO ACCESS TECHNOLOGY INTERFERENCE CANCELLATION
Abstract
Methods, systems, and devices for wireless communications are
described. The method may include an interference estimation
procedure that measures interference from radio access technologies
(RATs) different from cellular vehicle to everything (CV2X) on the
CV2X network at a user equipment (UE). A UE may record measurements
of interference on the CV2X network when no CV2X signal is present
during the last symbol of a subframe. Then, the UE may estimate the
noise plus interference measured during the empty symbol to improve
noise plus interference whitening when decoding a subframe.
Inventors: |
Landis; Shay; (Hod Hasharon,
IL) ; Touboul; Assaf; (Netanya, IL) ; Kutz;
Gideon Shlomo; (Ramat Hasharon, IL) ; Levitsky;
Michael; (Rehovot, IL) ; Bar-Or Tillinger; Amit;
(Petach Tikva, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
1000004883081 |
Appl. No.: |
16/891804 |
Filed: |
June 3, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62857370 |
Jun 5, 2019 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 84/12 20130101;
H04W 24/10 20130101; H04B 17/336 20150115; H04L 5/0082 20130101;
H04W 4/40 20180201; H04W 72/0446 20130101 |
International
Class: |
H04W 4/40 20060101
H04W004/40; H04W 24/10 20060101 H04W024/10; H04B 17/336 20060101
H04B017/336; H04L 5/00 20060101 H04L005/00; H04W 72/04 20060101
H04W072/04 |
Claims
1. A method for wireless communications by a user equipment (UE),
comprising: identifying, within a first transmission time interval
(TTI), a symbol period in which a set of wireless devices operating
in accordance with a cellular vehicle to everything (CV2X) radio
access technology (RAT) are configured to refrain from
transmitting; measuring interference of a second RAT during the
symbol period, the second RAT differing from the CV2X RAT; and
decoding a CV2X waveform during the first TTI or a second TTI based
at least in part on the measured interference.
2. The method of claim 1, wherein identifying the symbol period
comprises: identifying a preconfiguration or receiving control
signaling that configures the UE to refrain from transmitting
during the symbol period.
3. The method of claim 1, wherein identifying the symbol period
comprises: identifying that the symbol period is a last symbol
period of the first TTI, the first TTI comprising a plurality of
symbol periods.
4. The method of claim 1, wherein measuring the interference
comprises: generating, for the symbol period, a plurality of
interference measurements using a plurality of antennas of the UE;
and generating a covariance interference metric based at least in
part on the plurality of interference measurements, wherein the
CV2X waveform is decoded based at least in part on the covariance
interference metric.
5. The method of claim 1, further comprising: buffering samples of
the CV2X waveform generated for a plurality of symbol periods of
the first TTI that occur prior to the symbol period within the
first TTI, wherein the CV2X waveform is received during the first
TTI and decoded based at least in part on the buffered samples.
6. The method of claim 1, wherein measuring the interference
comprises: generating an interference power measurement for the
symbol period, wherein the CV2X waveform is decoded based at least
in part on the interference power measurement.
7. The method of claim 1, wherein measuring the interference
comprises: generating a noise statistic, an interference statistic,
or both, for the symbol period, wherein the CV2X waveform is
decoded based at least in part on the noise statistic, the
interference statistic, or both.
8. The method of claim 1, wherein decoding the CV2X waveform
comprises: decoding the CV2X waveform in the second TTI that occurs
after the first TTI based at least in part on the measured
interference.
9. The method of claim 8, wherein the second TTI occurs immediately
after the first TTI.
10. The method of claim 8, wherein at least one intervening TTI
occurs between the first TTI and the second TTI.
11. The method of claim 1, wherein decoding the CV2X waveform
comprises: applying noise whitening processing to the CV2X waveform
based at least in interference measurement.
12. The method of claim 1, wherein decoding the CV2X waveform
comprises: decoding the CV2X waveform in the first TTI.
13. The method of claim 1, wherein measuring the interference
comprises: measuring, for the symbol period, interference of at
least one additional RAT, wherein the CV2X waveform is decoded
based at least in part on the measured interference of the at least
one additional RAT.
14. The method of claim 1, further comprising: measuring
interference within a second symbol period, wherein the CV2X
waveform is decoded based at least in part on the interference
measured within the second symbol period.
15. The method of claim 1, wherein measuring the interference
comprises: measuring, during the symbol period, the interference of
a wireless local area network (WLAN) RAT.
16. The method of claim 1, wherein measuring the interference
comprises: measuring, during the symbol period, the interference of
a Long Term Evolution (LTE) RAT.
17. The method of claim 1, wherein the first TTI is a subframe.
18. An apparatus for wireless communications by a user equipment
(UE), comprising: a processor, memory coupled with the processor;
and instructions stored in the memory and executable by the
processor to cause the apparatus to: identify, within a first
transmission time interval (TTI), a symbol period in which a set of
wireless devices operating in accordance with a cellular vehicle to
everything (CV2X) radio access technology (RAT) are configured to
refrain from transmitting; measure interference of a second RAT
during the symbol period, the second RAT differing from the CV2X
RAT; and decode a CV2X waveform during the first TTI or a second
TTI based at least in part on the measured interference.
19. The apparatus of claim 18, further comprising a decoder,
wherein the instructions to decode the CV2X waveform are executable
by the processor to cause the apparatus to: configure the decoder
to decode the CV2X waveform during the first TTI or the second TTI
based at least in part on the measured interference.
20. The apparatus of claim 18, wherein the instructions to identify
the symbol period are executable by the processor to cause the
apparatus to: identify a preconfiguration or receiving control
signaling that configures the UE to refrain from transmitting
during the symbol period.
21. The apparatus of claim 18, wherein the instructions to identify
the symbol period are executable by the processor to cause the
apparatus to: identify that the symbol period is a last symbol
period of the first TTI, the first TTI comprising a plurality of
symbol periods.
22. The apparatus of claim 18, wherein the instructions to measure
the interference are executable by the processor to cause the
apparatus to: generate, for the symbol period, a plurality of
interference measurements using a plurality of antennas of the UE;
and generate a covariance interference metric based at least in
part on the plurality of interference measurements, wherein the
CV2X waveform is decoded based at least in part on the covariance
interference metric.
23. The apparatus of claim 18, wherein the instructions are further
executable by the processor to cause the apparatus to: buffer
samples of the CV2X waveform generated for a plurality of symbol
periods of the first TTI that occur prior to the symbol period
within the first TTI, wherein the CV2X waveform is received during
the first TTI and decoded based at least in part on the buffered
samples.
24. The apparatus of claim 18, wherein the instructions to measure
the interference are executable by the processor to cause the
apparatus to: generate an interference power measurement for the
symbol period, wherein the CV2X waveform is decoded based at least
in part on the interference power measurement.
25. The apparatus of claim 18, wherein the instructions to measure
the interference are executable by the processor to cause the
apparatus to: generate a noise statistic, an interference
statistic, or both, for the symbol period, wherein the CV2X
waveform is decoded based at least in part on the noise statistic,
the interference statistic, or both.
26. The apparatus of claim 18, wherein the instructions to decode
the CV2X waveform are executable by the processor to cause the
apparatus to: decode the CV2X waveform in the second TTI that
occurs after the first TTI based at least in part on the measured
interference.
27. The apparatus of claim 18, wherein the instructions to measure
the interference are executable by the processor to cause the
apparatus to: measure, for the symbol period, interference of at
least one additional RAT, wherein the CV2X waveform is decoded
based at least in part on the measured interference of the at least
one additional RAT.
28. The apparatus of claim 18, wherein the instructions are further
executable by the processor to cause the apparatus to: measure
interference within a second symbol period, wherein the CV2X
waveform is decoded based at least in part on the interference
measured within the second symbol period.
29. An apparatus for wireless communications by a user equipment
(UE), comprising: means for identifying, within a first
transmission time interval (TTI), a symbol period in which a set of
wireless devices operating in accordance with a cellular vehicle to
everything (CV2X) radio access technology (RAT) are configured to
refrain from transmitting; means for measuring interference of a
second RAT during the symbol period, the second RAT differing from
the CV2X RAT; and means for decoding a CV2X waveform during the
first TTI or a second TTI based at least in part on the measured
interference.
30. A non-transitory computer-readable medium storing code for
wireless communications by a user equipment (UE), the code
comprising instructions executable by a processor to: identify,
within a first transmission time interval (TTI), a symbol period in
which a set of wireless devices operating in accordance with a
cellular vehicle to everything (CV2X) radio access technology (RAT)
are configured to refrain from transmitting; measure interference
of a second RAT during the symbol period, the second RAT differing
from the CV2X RAT; and decode a CV2X waveform during the first TTI
or a second TTI based at least in part on the measured
interference.
Description
CROSS REFERENCE
[0001] The present application for patent claims the benefit of
U.S. Provisional Patent Application No. 62/857,370 by LANDIS et
al., entitled "INTER-RADIO ACCESS TECHNOLOGY INTERFERENCE
CANCELLATION," filed Jun. 5, 2019, assigned to the assignee hereof,
and expressly incorporated by reference herein.
FIELD OF TECHNOLOGY
[0002] The following relates generally to wireless communications
and more specifically to inter-radio access technology interference
cancellation.
BACKGROUND
[0003] Wireless communications systems are widely deployed to
provide various types of communication content such as voice,
video, packet data, messaging, broadcast, and so on. These systems
may be capable of supporting communication with multiple users by
sharing the available system resources (e.g., time, frequency, and
power). Examples of such multiple-access systems include fourth
generation (4G) systems such as Long Term Evolution (LTE) systems,
LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth
generation (5G) systems which may be referred to as New Radio (NR)
systems. These systems may employ technologies such as code
division multiple access (CDMA), time division multiple access
(TDMA), frequency division multiple access (FDMA), orthogonal
frequency division multiple access (OFDMA), or discrete Fourier
transform spread orthogonal frequency division multiplexing
(DFT-S-OFDM). A wireless multiple-access communications system may
include a number of base stations or network access nodes, each
simultaneously supporting communication for multiple communication
devices, which may be otherwise known as user equipment (UE).
[0004] Wireless communication systems may include or support
networks used for vehicle based communications, also referred to as
vehicle-to-everything (V2X) networks, vehicle-to-vehicle (V2V)
networks, cellular V2X (CV2X) networks, or other similar networks.
During CV2X communications, a UE may decode transmissions generated
by a UE operating in the CV2X network. However, in some instances,
transmissions from one or more radio access technologies (RATs)
different than CV2X may interfere with the transmission in the CV2X
network. Under these conditions, the CV2X transmission may be
degraded such that the receiving UE may not correctly decode the
CV2X transmission.
SUMMARY
[0005] The described techniques relate to improved methods,
systems, devices, and apparatuses that support inter-radio access
technology interference cancellation. Generally, the described
techniques provide for an interference estimation process that
efficiently measures interference from radio access technologies
(RATs) different from cellular vehicle-to-everything (CV2X) such as
wireless local area network (WLAN), which may also be referred to
herein as WIFI, or Long Term Evolution (LTE). For instance, a UE
may take interference measurements when no CV2X signal is
transmitted. This may be during the last symbol of a subframe
immediately prior to the subframe of interest. For example, UE may
assume that no CV2X signal is present in symbol 13 of a subframe
and may detect the WIFI interference in that symbol. Then, the UE
may estimate the noise plus WIFI interference measured during
symbol 13 to improve noise plus interference whitening in the
subsequent subframe. In some cases, this estimation and mitigation
of interference may occur for every subframe. For example, an
estimation may occur at symbol 13 of subframe n-1 and applied to
subframe n, an estimation may occur at symbol 13 of subframe n and
applied to subframe n+1, and so on. Additionally, a UE may estimate
LTE interference for improved decoding of subframe n. For example,
the UE may buffer the first thirteen symbols of a subframe (e.g.,
symbols 0 to 12 of subframe n) and then measure and estimate LTE
interference throughout the fourteenth symbol (e.g., symbol 13).
The UE may then decode the stored symbols of subframe n based on
the LTE interference measurement.
[0006] A method of wireless communications by a UE is described.
The method may include identifying, within a first transmission
time interval (TTI), a symbol period in which a set of wireless
devices operating in accordance with a cellular vehicle to
everything (CV2X) RAT are configured to refrain from transmitting,
measuring interference of a second RAT during the symbol period,
the second RAT differing from the CV2X RAT, and decoding a CV2X
waveform during the first TTI or a second TTI based on the measured
interference.
[0007] An apparatus for wireless communications by a UE is
described. The apparatus may include a processor, memory coupled
with the processor, and instructions stored in the memory. The
instructions may be executable by the processor to cause the
apparatus to identify, within a first TTI, a symbol period in which
a set of wireless devices operating in accordance with a cellular
vehicle to everything (CV2X) RAT are configured to refrain from
transmitting, measure interference of a second RAT during the
symbol period, the second RAT differing from the CV2X RAT, and
decode a CV2X waveform during the first TTI or a second TTI based
on the measured interference.
[0008] Another apparatus for wireless communications by a UE is
described. The apparatus may include means for identifying, within
a first TTI, a symbol period in which a set of wireless devices
operating in accordance with a cellular vehicle to everything
(CV2X) RAT are configured to refrain from transmitting, measuring
interference of a second RAT during the symbol period, the second
RAT differing from the CV2X RAT, and decoding a CV2X waveform
during the first TTI or a second TTI based on the measured
interference.
[0009] A non-transitory computer-readable medium storing code for
wireless communications by a UE is described. The code may include
instructions executable by a processor to identify, within a first
TTI, a symbol period in which a set of wireless devices operating
in accordance with a cellular vehicle to everything (CV2X) RAT are
configured to refrain from transmitting, measure interference of a
second RAT during the symbol period, the second RAT differing from
the CV2X RAT, and decode a CV2X waveform during the first TTI or a
second TTI based on the measured interference.
[0010] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein,
identifying the symbol period may include operations, features,
means, or instructions for identifying a preconfiguration or
receiving control signaling that configures the UE to refrain from
transmitting during the symbol period.
[0011] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein,
identifying the symbol period may include operations, features,
means, or instructions for identifying that the symbol period may
be a last symbol period of the first TTI, the first TTI including a
set of symbol periods.
[0012] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, measuring
the interference may include operations, features, means, or
instructions for generating, for the symbol period, a set of
interference measurements using a set of antennas of the UE, and
generating a covariance interference metric based on the set of
interference measurements, where the CV2X waveform may be decoded
based on the covariance interference metric.
[0013] Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for buffering samples
of the CV2X waveform generated for a set of symbol periods of the
first TTI that occur prior to the symbol period within the first
TTI, where the CV2X waveform may be received during the first TTI
and decoded based on the buffered samples.
[0014] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, measuring
the interference may include operations, features, means, or
instructions for generating an interference power measurement for
the symbol period, where the CV2X waveform may be decoded based on
the interference power measurement.
[0015] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, measuring
the interference may include operations, features, means, or
instructions for generating a noise statistic, an interference
statistic, or both, for the symbol period, where the CV2X waveform
may be decoded based on the noise statistic, the interference
statistic, or both.
[0016] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, decoding
the CV2X waveform may include operations, features, means, or
instructions for decoding the CV2X waveform in the second TTI that
occurs after the first TTI based on the measured interference.
[0017] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, the
second TTI occurs immediately after the first TTI.
[0018] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, at least
one intervening TTI occurs between the first TTI and the second
TTI.
[0019] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, decoding
the CV2X waveform may include operations, features, means, or
instructions for applying noise whitening processing to the CV2X
waveform based at least in interference measurement.
[0020] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, decoding
the CV2X waveform may include operations, features, means, or
instructions for decoding the CV2X waveform in the first TTI.
[0021] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, measuring
the interference may include operations, features, means, or
instructions for measuring, for the symbol period, interference of
at least one additional RAT, where the CV2X waveform may be decoded
based on the measured interference of the at least one additional
RAT.
[0022] Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for measuring
interference within a second symbol period, where the CV2X waveform
may be decoded based on the interference measured within the second
symbol period.
[0023] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, measuring
the interference may include operations, features, means, or
instructions for measuring, during the symbol period, the
interference of a WLAN RAT.
[0024] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, measuring
the interference may include operations, features, means, or
instructions for measuring, during the symbol period, the
interference of an LTE RAT.
[0025] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, the first
TTI may be a subframe.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 illustrates an example of a system for wireless
communications in accordance with aspects of the present
disclosure.
[0027] FIG. 2 illustrates an example of a system for wireless
communications in accordance with aspects of the present
disclosure.
[0028] FIG. 3 illustrates an example of a subframe structure in
accordance with aspects of the present disclosure.
[0029] FIG. 4 illustrates an example of a process flow in
accordance with aspects of the present disclosure.
[0030] FIGS. 5 and 6 show block diagrams of devices in accordance
with aspects of the present disclosure.
[0031] FIG. 7 shows a block diagram of a communications manager in
accordance with aspects of the present disclosure.
[0032] FIG. 8 shows a diagram of a system including a device in
accordance with aspects of the present disclosure.
[0033] FIGS. 9 through 12 show flowcharts illustrating methods in
accordance with aspects of the present disclosure.
DETAILED DESCRIPTION
[0034] The described techniques relate to improved methods,
systems, devices, and apparatuses that support inter-radio access
technology interference cancellation. Generally, the described
techniques provide for an interference estimation process that
efficiently measures interference from radio access technologies
(RATs) different from cellular vehicle-to-everything (CV2X). Common
interference mitigation approaches estimate channel interference on
pilot signals used for channel estimation. This approach may have
large complexity and may introduce delay into the system. The large
complexity translates to high power consumption, which may be
prohibitive for cellular vehicle to everything (CV2X) applications.
For instance high power consumption may lead to temperature issues
such as increased temperatures that the chip may not be able to
withstand.
[0035] The present disclosure describes an interference estimation
procedure that efficiently measures interference from radio access
technologies (RATs) different from CV2X (e.g., WIFI and/or LTE).
For instance, a UE may take interference measurements when no CV2X
signal is present. This may be during the last symbol of a subframe
immediately prior to a subframe of interest. For example, the UE
may assume that no CV2X signal is present in symbol 13 of a
subframe and may detect the WIFI interference in that symbol. Then,
the UE may estimate the noise plus WIFI interference measured
during symbol 13 to improve noise plus interference whitening in
the subsequent subframe. In some cases, this estimation and
mitigation of interference may occur for every subframe. For
example, an estimation may occur at symbol 13 of subframe n-1 and
applied to subframe n, an estimation may occur at symbol 13 of
subframe n and applied to subframe n+1, and so on. Additionally, a
UE may estimate LTE interference for improved decoding of subframe
n. For example, the UE may buffer the first thirteen symbols of a
subframe (e.g., symbols 0 to 12 of subframe n) and then measure and
estimate LTE interference throughout the fourteenth symbol (e.g.,
symbol 13). The UE may then decode the stored symbols of subframe n
based on the LTE interference measurement.
[0036] The procedure described herein may allow a UE to estimate
interference where no CV2X signal is present that leads to a better
interference statistics estimation than common methodologies.
Additionally, the computation complexity is less than current
methodologies, which may improve the speed of communication by not
introducing significant latency into the CV2X communications.
[0037] Aspects of the disclosure are initially described in the
context of a wireless communications system. Aspects of the
disclosure are further illustrated by and described with reference
to apparatus diagrams, system diagrams, and flowcharts that relate
to inter-radio access technology interference cancellation.
[0038] FIG. 1 illustrates an example of a wireless communications
system 100 that supports inter-radio access technology interference
cancellation in accordance with aspects of the present disclosure.
The wireless communications system 100 may include base stations
105, UEs 115, and a core network 130. In some examples, the
wireless communications system 100 may be a Long Term Evolution
(LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro
network, or a New Radio (NR) network. In some cases, the wireless
communications system 100 may support enhanced broadband
communications, ultra-reliable (e.g., mission critical)
communications, low latency communications, communications with
low-cost and low-complexity devices, or any combination
thereof.
[0039] Base stations 105 may be dispersed throughout a geographic
area to form the wireless communications system 100 and may be
devices in different forms or having different capabilities. Base
stations 105 and UEs 115 may wirelessly communicate via one or more
communication links 125. Each base station 105 may provide a
coverage area 110 over which UEs 115 and the base station 105 may
establish communication links 125. The coverage area 110 may be an
example of a geographic area over which a base station 105 and a UE
115 support the communication of signals according to one or more
radio access technologies.
[0040] UEs 115 may be dispersed throughout a coverage area 110 of
the wireless communications system 100, and each UE 115 may be
stationary, or mobile, or both at different times. UEs 115 may be
devices in different forms or having different capabilities. Some
example UEs 115 are illustrated in FIG. 1. The UEs 115 described
herein may be able to communicate with various types of devices,
such as other UEs 115, base stations 105, and/or network equipment
(e.g., core network nodes, relay devices, integrated access and
backhaul (IAB) nodes, or other network equipment), as shown in FIG.
1.
[0041] Base stations 105 may communicate with the core network 130,
or with one another, or both. For example, base stations 105 may
interface with the core network 130 through backhaul links 120
(e.g., via an S1, N2, N3, or other interface). Base stations 105
may communicate with one another over backhaul links 120 (e.g., via
an X2, Xn, or other interface) either directly (e.g., directly
between base stations 105), or indirectly (e.g., via core network
130), or both. In some examples, backhaul links 120 may be or
include one or more wireless links.
[0042] One or more of base stations 105 described herein may
include or may be referred to by a person of ordinary skill in the
art as a base transceiver station, a radio base station, an access
point, a radio transceiver, a NodeB, an eNodeB (eNB), a
next-generation NodeB or giga-NodeB (either of which may be
referred to as a gNB), a Home NodeB, a Home eNodeB, or other
suitable terminology.
[0043] A UE 115 may include or may be referred to as a mobile
device, a wireless device, a remote device, a handheld device, or a
subscriber device, or some other suitable terminology, where the
"device" may also be referred to as a unit, a station, a terminal,
or a client, among other examples. A UE 115 may also include or may
be referred to as a personal electronic device such as a cellular
phone, a personal digital assistant (PDA), a tablet computer, a
laptop computer, or a personal computer. In some examples, a UE 115
may include or be referred to as a wireless local loop (WLL)
station, an Internet of Things (IoT) device, an Internet of
Everything (IoE) device, a machine type communications (MTC)
device, or the like, which may be implemented in various objects
such as appliances, vehicles, meters, or the like.
[0044] The UEs 115 described herein may be able to communicate with
various types of devices, such as other UEs 115 that may sometimes
act as relays as well as base stations 105 and network equipment
including macro eNBs or gNBs, small cell eNBs or gNBs, relay base
stations, and the like, as shown in FIG. 1.
[0045] UEs 115 and base stations 105 may wirelessly communicate
with one another via one or more communication links 125 over one
or more carriers. The term "carrier" may refer to a set of radio
frequency spectrum resources having a defined physical layer
structure for supporting communication links 125. For example, a
carrier used for a communication link 125 may include a portion of
a radio frequency spectrum band (e.g., a bandwidth part (BWP)) that
is operated according to physical layer channels for a given radio
access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical
layer channel may carry acquisition signaling (e.g.,
synchronization signals, system information), control signaling
that coordinates operation for the carrier, user data, or other
signaling. The wireless communications system 100 may support
communication with a UE 115 using carrier aggregation or
multi-carrier operation. A UE 115 may be configured with multiple
downlink component carriers and one or more uplink component
carriers according to a carrier aggregation configuration. Carrier
aggregation may be used with both frequency division duplexing
(FDD) and time division duplexing (TDD) component carriers.
[0046] In some examples (e.g., in a carrier aggregation
configuration), a carrier may also have acquisition signaling or
control signaling that coordinates operations for other carriers. A
carrier may be associated with a frequency channel (e.g., an
evolved universal mobile telecommunication system terrestrial radio
access (E-UTRA) absolute radio frequency channel number (EARFCN))
and may be positioned according to a channel raster for discovery
by UEs 115. A carrier may be operated in a standalone mode where
initial acquisition and connection may be conducted by UEs 115 via
the carrier, or the carrier may be operated in a non-standalone
mode where a connection is anchored using a different carrier
(e.g., of the same or a different radio access technology).
[0047] Communication links 125 shown in the wireless communications
system 100 may include uplink transmissions from a UE 115 to a base
station 105, or downlink transmissions from a base station 105 to a
UE 115. Carriers may carry downlink or uplink communications (e.g.,
in an FDD mode) or may be configured to carry downlink and uplink
communications (e.g., in a TDD mode).
[0048] A carrier may be associated with a particular bandwidth of
the radio frequency spectrum, and in some examples the carrier
bandwidth may be referred to as a "system bandwidth" of the carrier
or the wireless communications system 100. For example, the carrier
bandwidth may be one of a number of predetermined bandwidths for
carriers of a particular radio access technology (e.g., 1.4, 3, 5,
10, 15, 20, 40, or 80 megahertz (MHz)). Devices of the wireless
communications system 100 (e.g., base stations 105, UEs 115, or
both) may have hardware configurations that support communications
over a particular carrier bandwidth or may be configurable to
support communications over one of a set of carrier bandwidths. In
some examples, the wireless communications system 100 may include
base stations 105 and/or UEs 115 that support simultaneous
communications via carriers associated with multiple carrier
bandwidths. In some examples, each served UE 115 may be configured
for operating over portions (e.g., a sub-band, a BWP) or all of a
carrier bandwidth.
[0049] Signal waveforms transmitted over a carrier may be made up
of multiple subcarriers (e.g., using multi-carrier modulation (MCM)
techniques such as orthogonal frequency division multiplexing
(OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In
a system employing MCM techniques, a resource element may consist
of one symbol period (e.g., a duration of one modulation symbol)
and one subcarrier, where the symbol period and subcarrier spacing
are inversely related. The number of bits carried by each resource
element may depend on the modulation scheme (e.g., the order of the
modulation scheme, the coding rate of the modulation scheme, or
both). Thus, the more resource elements that a UE 115 receives and
the higher the order of the modulation scheme, the higher the data
rate may be for the UE 115. A wireless communications resource may
refer to a combination of a radio frequency spectrum resource, a
time resource, and a spatial resource (e.g., spatial layers or
beams), and the use of multiple spatial layers may further increase
the data rate or data integrity for communications with a UE
115.
[0050] One or more numerologies for a carrier may be supported,
where a numerology may include a subcarrier spacing (.DELTA.f) and
a cyclic prefix. A carrier may be divided into BWPs having the same
or different numerologies. In some examples, a UE 115 may be
configured with multiple BWPs. In some cases, a single BWP for a
carrier is active at a given time, and communications for the UE
115 may be restricted to active BWPs.
[0051] Time intervals for base stations 105 or UEs 115 may be
expressed in multiples of a basic time unit which may, for example,
refer to a sampling period of T.sub.s=1/(.DELTA.f.sub.maxN.sub.f)
seconds, where .DELTA.f.sub.max may represent the maximum supported
subcarrier spacing, and N.sub.f may represent the maximum supported
discrete Fourier transform (DFT) size. Time intervals of a
communications resource may be organized according to radio frames
each having a specified duration (e.g., 10 milliseconds (ms)). Each
radio frame may be identified by a system frame number (SFN) (e.g.,
ranging from 0 to 1023).
[0052] Each frame may include multiple consecutively numbered
subframes or slots, and each subframe or slot may have the same
duration. In some cases, a frame may be divided into subframes, and
each subframe may be further divided into a number of slots.
Alternatively, each frame may include a variable number of slots,
and the number of slots may depend on subcarrier spacing. Each slot
may include a number of symbol periods (e.g., depending on the
length of the cyclic prefix prepended to each symbol period). In
some wireless communications systems 100, a slot may further be
divided into multiple mini-slots containing one or more symbols.
Excluding the cyclic prefix, each symbol period may contain one or
more (e.g., N.sub.f) sampling periods. The duration of a symbol
period may depend on the subcarrier spacing or frequency band of
operation.
[0053] A subframe, a slot, a mini-slot, or a symbol may be the
smallest scheduling unit of the wireless communications system 100
and may be referred to as a transmission time interval (TTI). In
some cases, the TTI duration (that is, the number of symbol periods
in a TTI) may be variable. Additionally or alternatively, the
smallest scheduling unit of the wireless communications system 100
may be dynamically selected (e.g., in bursts of shortened TTIs
(sTTIs)).
[0054] Physical channels may be multiplexed on a carrier according
to various techniques. A physical control channel and a physical
data channel may be multiplexed on a downlink carrier, for example,
using time division multiplexing (TDM) techniques, frequency
division multiplexing (FDM) techniques, or hybrid TDM-FDM
techniques. A control region (e.g., a control resource set
(CORESET)) for a physical control channel may be defined by a
number of symbol periods and may extend across the system bandwidth
or a subset of the system bandwidth of the carrier. One or more
control regions (e.g., CORESETs) may be configured for a set of UEs
115. For example, UEs 115 may monitor or search control regions for
control information according to one or more search space sets, and
each search space set may include one or multiple control channel
candidates in one or more aggregation levels arranged in a cascaded
manner. An aggregation level for a control channel candidate may
refer to a number of control channel resources (e.g., control
channel elements (CCEs)) associated with encoded information for a
control information format having a given payload size. Search
space sets may include common search space sets configured for
sending control information to multiple UEs 115 and UE-specific
search space sets for sending control information to a specific UE
115.
[0055] Each base station 105 may provide communication coverage via
one or more cells, for example a macro cell, a small cell, a hot
spot, or other types of cells, or various combinations thereof. The
term "cell" may refer to a logical communication entity used for
communication with a base station 105 (e.g., over a carrier) and
may be associated with an identifier for distinguishing neighboring
cells (e.g., a physical cell identifier (PCID), a virtual cell
identifier (VCID), or others). In some examples, a cell may also
refer to a geographic coverage area 110 or a portion of a
geographic coverage area 110 (e.g., a sector) over which the
logical communication entity operates. Such cells may range from
smaller areas (e.g., a structure, a subset of structure) to larger
areas depending on various factors such as the capabilities of the
base station 105. For example, a cell may be or include a building,
a subset of a building, exterior spaces between or overlapping with
geographic coverage areas 110, or the like.
[0056] A macro cell generally covers a relatively large geographic
area (e.g., several kilometers in radius) and may allow
unrestricted access by UEs 115 with service subscriptions with the
network provider supporting the macro cell. A small cell may be
associated with a lower-powered base station 105, as compared with
a macro cell, and a small cell may operate in the same or different
(e.g., licensed, unlicensed) frequency bands as macro cells. Small
cells may provide unrestricted access to UEs 115 with service
subscriptions with the network provider or may provide restricted
access to UEs 115 having an association with the small cell (e.g.,
UEs 115 in a closed subscriber group (CSG), UEs 115 associated with
users in a home or office, and the like). A base station 105 may
support one or multiple cells and may also support communications
over the one or more cells using one or multiple component
carriers.
[0057] In some examples, a carrier may support multiple cells, and
different cells may be configured according to different protocol
types (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile
broadband (eMBB), or others) that may provide access for different
types of devices.
[0058] In some examples, a base station 105 may be movable and
therefore provide communication coverage for a moving geographic
coverage area 110. In some examples, different geographic coverage
areas 110 associated with different technologies may overlap, but
the different geographic coverage areas 110 may be supported by the
same base station 105. In other examples, overlapping geographic
coverage areas 110 associated with different technologies may be
supported by different base stations 105. The wireless
communications system 100 may include, for example, a heterogeneous
network in which different types of base stations 105 provide
coverage for various geographic coverage areas 110 using the same
or different radio access technologies.
[0059] Some UEs 115, such as MTC or IoT devices, may be low cost or
low complexity devices and may provide for automated communication
between machines (e.g., via Machine-to-Machine (M2M)
communication). M2M communication or MTC may refer to data
communication technologies that allow devices to communicate with
one another or a base station 105 without human intervention. In
some examples, M2M communication or MTC may include communications
from devices that integrate sensors or meters to measure or capture
information and relay such information to a central server or
application program that makes use of the information or presents
the information to humans interacting with the application program.
Some UEs 115 may be designed to collect information or enable
automated behavior of machines or other devices. Examples of
applications for MTC devices include smart metering, inventory
monitoring, water level monitoring, equipment monitoring,
healthcare monitoring, wildlife monitoring, weather and geological
event monitoring, fleet management and tracking, remote security
sensing, physical access control, and transaction-based business
charging.
[0060] The wireless communications system 100 may be configured to
support ultra-reliable communications or low-latency
communications, or various combinations thereof. For example, the
wireless communications system 100 may be configured to support
ultra-reliable low-latency communications (URLLC) or mission
critical communications. UEs 115 may be designed to support
ultra-reliable, low-latency, or critical functions (e.g., mission
critical functions). Ultra-reliable communications may include
private communication or group communication and may be supported
by one or more mission critical services such as mission critical
push-to-talk (MCPTT), mission critical video (MCVideo), or mission
critical data (MCData). Support for mission critical functions may
include prioritization of services, and mission critical services
may be used for public safety or general commercial applications.
The terms ultra-reliable, low-latency, mission critical, and
ultra-reliable low-latency may be used interchangeably herein.
[0061] In some cases, a UE 115 may also be able to communicate
directly with other UEs 115 over a device-to-device (D2D)
communication link 135 (e.g., using a peer-to-peer (P2P) or D2D
protocol). One or more UEs 115 utilizing D2D communications may be
within the geographic coverage area 110 of a base station 105.
Other UEs 115 in such a group may be outside the geographic
coverage area 110 of a base station 105 or be otherwise unable to
receive transmissions from a base station 105. In some cases,
groups of UEs 115 communicating via D2D communications may utilize
a one-to-many (1:M) system in which each UE 115 transmits to every
other UE 115 in the group. In some examples, a base station 105
facilitates the scheduling of resources for D2D communications. In
other cases, D2D communications are carried out between UEs 115
without the involvement of a base station 105.
[0062] In some systems, the D2D communication link 135 may be an
example of a communication channel, such as a sidelink
communication channel, between vehicles (e.g., UEs 115). In some
examples, vehicles may communicate using vehicle-to-everything
(V2X) communications, vehicle-to-vehicle (V2V) communications, or
some combination of these. A vehicle may signal information related
to traffic conditions, signal scheduling, weather, safety,
emergencies, or any other information relevant to a V2X system. In
some cases, vehicles in a V2X system may communicate with roadside
infrastructure, such as roadside units, or with the network via one
or more network nodes (e.g., base stations 105) using
vehicle-to-network (V2N) communications, or with both.
[0063] The core network 130 may provide user authentication, access
authorization, tracking, Internet Protocol (IP) connectivity, and
other access, routing, or mobility functions. The core network 130
may be an evolved packet core (EPC) or 5G core (5GC), which may
include at least one control plane entity that manages access and
mobility (e.g., a mobility management entity (MME), an access and
mobility management function (AMF)) and at least one user plane
entity that routes packets or interconnects to external networks
(e.g., a serving gateway (S-GW), a Packet Data Network (PDN)
gateway (P-GW), a user plane function (UPF)). The control plane
entity may manage non-access stratum (NAS) functions such as
mobility, authentication, and bearer management for UEs 115 served
by base stations 105 associated with the core network 130. User IP
packets may be transferred through the user plane entity, which may
provide IP address allocation as well as other functions. The user
plane entity may be connected to the network operators IP services
150. The operators IP services 150 may include access to the
Internet, Intranet(s), an IP Multimedia Subsystem (IMS), or a
Packet-Switched Streaming Service.
[0064] Some of the network devices, such as a base station 105, may
include subcomponents such as an access network entity 140, which
may be an example of an access node controller (ANC). Each access
network entity 140 may communicate with UEs 115 through a number of
other access network transmission entities 145, which may be
referred to as radio heads, smart radio heads, or
transmission/reception points (TRPs). Each access network
transmission entity 145 may include one or more antenna panels. In
some configurations, various functions of each access network
entity 140 or base station 105 may be distributed across various
network devices (e.g., radio heads and ANCs) or consolidated into a
single network device (e.g., a base station 105).
[0065] The wireless communications system 100 may operate using one
or more frequency bands, typically in the range of 300 megahertz
(MHz) to 300 gigahertz (GHz). Generally, the region from 300 MHz to
3 GHz is known as the ultra-high frequency (UHF) region or
decimeter band, since the wavelengths range from approximately one
decimeter to one meter in length. UHF waves may be blocked or
redirected by buildings and environmental features, but the waves
may penetrate structures sufficiently for a macro cell to provide
service to UEs 115 located indoors. Transmission of UHF waves may
be associated with smaller antennas and shorter ranges (e.g., less
than 100 kilometers) compared to transmission using the smaller
frequencies and longer waves of the high frequency (HF) or very
high frequency (VHF) portion of the spectrum below 300 MHz.
[0066] The wireless communications system 100 may also operate in a
super high frequency (SHF) region using frequency bands from 3 GHz
to 30 GHz, also known as the centimeter band, or in an extremely
high frequency (EHF) region of the spectrum (e.g., from 30 GHz to
300 GHz), also known as the millimeter band. In some examples, the
wireless communications system 100 may support millimeter wave
(mmW) communications between UEs 115 and base stations 105, and EHF
antennas of the respective devices may be smaller and more closely
spaced than UHF antennas. In some cases, this may facilitate use of
antenna arrays within a device. The propagation of EHF
transmissions, however, may be subject to even greater atmospheric
attenuation and shorter range than SHF or UHF transmissions.
Techniques disclosed herein may be employed across transmissions
that use one or more different frequency regions, and designated
use of bands across these frequency regions may differ by country
or regulating body.
[0067] The wireless communications system 100 may utilize both
licensed and unlicensed radio frequency spectrum bands. For
example, the wireless communications system 100 may employ License
Assisted Access (LAA), LTE-Unlicensed (LTE-U) radio access
technology, or NR technology in an unlicensed band such as the 5
GHz industrial, scientific, and medical (ISM) band. When operating
in unlicensed radio frequency spectrum bands, devices such as base
stations 105 and UEs 115 may employ carrier sensing for collision
detection and avoidance. In some cases, operations in unlicensed
bands may be based on a carrier aggregation configuration in
conjunction with component carriers operating in a licensed band
(e.g., LAA). Operations in unlicensed spectrum may include downlink
transmissions, uplink transmissions, P2P transmissions, D2D
transmissions, or the like.
[0068] A base station 105 or UE 115 may be equipped with multiple
antennas, which may be used to employ techniques such as transmit
diversity, receive diversity, multiple-input multiple-output (MIMO)
communications, or beamforming. The antennas of a base station 105
or UE 115 may be located within one or more antenna arrays or
antenna panels, which may support MIMO operations or transmit or
receive beamforming. For example, one or more base station antennas
or antenna arrays may be co-located at an antenna assembly, such as
an antenna tower. In some cases, antennas or antenna arrays
associated with a base station 105 may be located in diverse
geographic locations. A base station 105 may have an antenna array
with a number of rows and columns of antenna ports that the base
station 105 may use to support beamforming of communications with a
UE 115. Likewise, a UE 115 may have one or more antenna arrays that
may support various MIMO or beamforming operations. Additionally or
alternatively, an antenna panel may support radio frequency
beamforming for a signal transmitted via an antenna port.
[0069] Base stations 105 or UEs 115 may use MIMO communications to
exploit multipath signal propagation and increase the spectral
efficiency by transmitting or receiving multiple signals via
different spatial layers. Such techniques may be referred to as
spatial multiplexing. The multiple signals may, for example, be
transmitted by the transmitting device via different antennas or
different combinations of antennas. Likewise, the multiple signals
may be received by the receiving device via different antennas or
different combinations of antennas. Each of the multiple signals
may be referred to as a separate spatial stream and may carry bits
associated with the same data stream (e.g., the same codeword) or
different data streams (e.g., different codewords). Different
spatial layers may be associated with different antenna ports used
for channel measurement and reporting. MIMO techniques include
single-user MIMO (SU-MIMO), where multiple spatial layers are
transmitted to the same receiving device, and multiple-user MIMO
(MU-MIMO), where multiple spatial layers are transmitted to
multiple devices.
[0070] Beamforming, which may also be referred to as spatial
filtering, directional transmission, or directional reception, is a
signal processing technique that may be used at a transmitting
device or a receiving device (e.g., a base station 105 or a UE 115)
to shape or steer an antenna beam (e.g., a transmit beam, a receive
beam) along a spatial path between the transmitting device and the
receiving device. Beamforming may be achieved by combining the
signals communicated via antenna elements of an antenna array such
that some signals propagating at particular orientations with
respect to an antenna array experience constructive interference
while others experience destructive interference. The adjustment of
signals communicated via the antenna elements may include a
transmitting device or a receiving device applying certain
amplitude offsets, phase offsets, or both to signals carried via
the antenna elements associated with the device. The adjustments
associated with each of the antenna elements may be defined by a
beamforming weight set associated with a particular orientation
(e.g., with respect to the antenna array of the transmitting device
or receiving device, or with respect to some other
orientation).
[0071] A receiving device (e.g., a UE 115) may try multiple receive
configurations (e.g., directional listening) when receiving various
signals from the base station 105, such as synchronization signals,
reference signals, beam selection signals, or other control
signals. For example, a receiving device may try multiple receive
directions by receiving via different antenna subarrays, by
processing received signals according to different antenna
subarrays, by receiving according to different receive beamforming
weight sets (e.g., different directional listening weight sets)
applied to signals received at multiple antenna elements of an
antenna array, or by processing received signals according to
different receive beamforming weight sets applied to signals
received at multiple antenna elements of an antenna array, any of
which may be referred to as "listening" according to different
receive configurations or receive directions. In some examples, a
receiving device may use a single receive configuration to receive
along a single beam direction (e.g., when receiving a data signal).
The single receive configuration may be aligned in a beam direction
determined based on listening according to different receive
configuration directions (e.g., a beam direction determined to have
a highest signal strength, highest signal-to-noise ratio (SNR), or
otherwise acceptable signal quality based on listening according to
multiple beam directions).
[0072] The wireless communications system 100 may be a packet-based
network that operates according to a layered protocol stack. In the
user plane, communications at the bearer or Packet Data Convergence
Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC)
layer may perform packet segmentation and reassembly to communicate
over logical channels. A Medium Access Control (MAC) layer may
perform priority handling and multiplexing of logical channels into
transport channels. The MAC layer may also use error detection
techniques, error correction techniques, or both to support
retransmissions at the MAC layer to improve link efficiency. In the
control plane, the Radio Resource Control (RRC) protocol layer may
provide establishment, configuration, and maintenance of an RRC
connection between a UE 115 and a base station 105 or core network
130 supporting radio bearers for user plane data. At the Physical
layer, transport channels may be mapped to physical channels.
[0073] UEs 115 and base stations 105 may support retransmissions of
data to increase the likelihood that data is received successfully.
Hybrid automatic repeat request (HARQ) feedback is one technique
for increasing the likelihood that data is received correctly over
a communication link 125. HARQ may include a combination of error
detection (e.g., using a cyclic redundancy check (CRC)), forward
error correction (FEC), and retransmission (e.g., automatic repeat
request (ARQ)). HARQ may improve throughput at the MAC layer in
poor radio conditions (e.g., low signal-to-noise conditions). In
some cases, a device may support same-slot HARQ feedback, where the
device may provide HARQ feedback in a specific slot for data
received in a previous symbol in the slot. In other cases, the
device may provide HARQ feedback in a subsequent slot, or according
to some other time interval.
[0074] An interference estimation procedure that efficiently
measures interference from radio access technologies (RATs)
different from CV2X (e.g., WIFI and/or LTE) may be performed at UE
115. For instance, UE 115 may take interference measurements when
no CV2X signal is present during the last symbol of a subframe
immediately prior to the subframe of interest. For example, UE 115
may assume that no CV2X signal is present in symbol 13 of a
subframe and may detect the WIFI interference in that symbol. Then,
UE 115 may estimate the noise plus WIFI interference measured
during symbol 13 to improve noise plus interference whitening in
the following subframe. For example, an estimation may occur at
symbol 13 of subframe n-1 and applied to subframe n, an estimation
may occur at symbol 13 of subframe n and applied to subframe n+1,
and so on. Additionally, UE 115 may estimate LTE interference for
improved decoding of subframe n. For example, UE 115 may buffer the
first thirteen symbols of a subframe (e.g., symbols 0 to 12 of
subframe n) and then measure and estimate LTE interference
throughout the fourteenth symbol (e.g., symbol 13). UE 115 may then
decode the stored symbols of subframe n based on the LTE
interference measurement.
[0075] FIG. 2 illustrates an example of a wireless communications
system 200 that supports inter-radio access technology interference
cancellation in accordance with aspects of the present disclosure.
In some examples, wireless communications system 200 may implement
aspects of wireless communications system 100. Wireless
communications system 200 may include base stations 105-a and
105-b, and UEs 115-a and 115-b, which may be examples of
corresponding base stations 105 and UEs 115, respectively, as
described herein with reference to FIG. 1.
[0076] In some cases, UE 115-a may communicate with UE 115-b (e.g.,
a data transmission) using the CV2X network (e.g., sidelink
communication via CV2X) on antennas 220-a and 220-c via link 205-c.
UE 115-a and UE 115-b may be capable of communicating on an
additional RAT with base station 105-a (e.g., an access point that
operates in accordance with a wireless local area network (WLAN)
RAT such as WIFI) and/or with base station 105-b (e.g., a base
station that operates in accordance with an LTE RAT). For instance,
base station 105-a may communicate with UE 115-b on antenna 220-d
via link 205-a. Additionally or alternatively, base station 105-b
may communicate with UE 115-b on antenna 220-d via link 205-b.
[0077] In some cases, a transmission (e.g., 205-a) from base
station 105-a (e.g., a WLAN AP) may interfere with the CV2X
communication between UE 115-a and 115-b on link 205-c. The
interfering transmission may be transmitted to UE 115-b or to
another UE 115 not shown, which may or may not be in communication
with UE 115-a. According to aspects of this disclosure, CV2X may be
operate in the Intelligent Transport System (ITS) band that
neighbors one or more frequency bands used for the WLAN RAT (e.g.,
one or more WIFI channels may be close in frequency to the ITS
band). In some cases, the WIFI channel TTI may not be aligned in
time with the CV2X channel TTI, and WIFI transmissions may not be
synchronous with CV2X transmissions. In some cases, interference
from the WIFI channels of base station 105-a may leak into a CV2X
frequency band used for link 205-c. This interference may impact
the CV2X receiver's (e.g., UE 115-a or UE 115-b) performance by
degrading the signal quality (e.g., SNR) of one or more CV2X
transmissions.
[0078] It may be beneficial to estimate the interference from base
station 105-a on link 205-c at antenna 220-a to improve signal
quality of the CV2X transmission on link 205-c. However, estimating
the interference inside of a CV2X subframe may complicated, consume
a large amount of power, and may result in delays of the
communication between UE 115-a and 115-b.
[0079] Additionally, a transmission (e.g., 205-b) from base station
105-b (e.g., an LTE base station) may interfere with the CV2X
communication between UE 115-a and 115-b on link 205-c. The
interfering transmission may be transmitted to UE 115-b or to
another UE 115 not shown, which may or may not be in communication
with UE 115-a. In some cases, interference from the LTE channels of
base station 105-b may leak into a CV2X frequency band used for
link 205-c. This interference may largely impact the CV2X
receiver's (e.g., UE 115-a or UE 115-b) performance by degrading
the signal quality (e.g., SNR) of one or more CV2X transmissions.
Therefore, it may also be beneficial to estimate the interference
from base station 105-b on link 205-c at antenna 220-a to improve
signal quality of the CV2X transmission on link 205-c. However,
estimating the interference of an LTE channel on a CV2X subframe
may be complicated due to the rapid change of waveforms on the LTE
channel on link 205-b. For example, a new waveform may be present
in each LTE subframe.
[0080] A procedure for estimating WIFI interference (e.g., from
base station 105-a) statistics and/or optionally LTE interference
(e.g., from base station 105-b) statistics on CV2X (e.g., sidelink
communication on link 205-c) with low complexity is described
herein. The estimation may occur during a time period when CV2X
transmissions are not transmitted. In some examples, the
interference estimation procedure may generate a covariance
interference metric (e.g., covariance matrix) to define and then
cancel interference. For instance, a two by two covariance matrix
R, as shown in equation 1, may be generated for the noise plus
interference (e.g., WIFI interference) of a frequency of CV2X based
on measurements taken when no CV2X communications occurred at two
receive antennas of UE 115-a.
R = [ r 11 r 1 2 r 2 1 r 2 2 ] ( 1 ) ##EQU00001##
[0081] In matrix R, the covariance between an interfering signal
and a CV2X signal may be measured at a number of receiver antennas
(e.g., two antennas 220-a and 220-b). The mean of the absolute
squared values of diagonal elements r.sub.11 and r.sub.22 may
represent the sum of the power of the detected noise plus
interference received at antennas 220-a and 220-b. The off diagonal
elements r.sub.12 and r.sub.21 may represent the conjugate
multiplicative at each receiver antenna per time sample. The matrix
may be applied by UE 115-a and/or 115-b to whiten the noise plus
interference on the receiver antennas (e.g., antennas 220-a and
220-b or 220-c and 220-d) for CV2X communications between UEs 115-a
and 115-b. The whitening of the noise plus interference may allow
UE 115-a to improve the performance of CV2X communication link
205-c with UE 115-b by increasing the success of decoding received
CV2X transmissions at UE 115-a. The estimation and/or whitening of
interference may be applied to one or more CV2X subframes based on
the variance of interference. Additionally, the UE 115-a may
generate UE 115-a and/or 115-b may also generate statistics by
monitoring noise and/or interference (e.g., WIFI interference, LTE
interference, or both) over time, and use generated the generated
statistics for noise cancellation. The statistics may include, for
example, average noise power, average interference power, or the
like.
[0082] FIG. 3 illustrates an example of a subframe structure 300
that supports inter-radio access technology interference
cancellation in accordance with aspects of the present disclosure.
In some examples, subframe structure 300 may implement aspects of
wireless communications systems 100 and/or 200. The subframe
structure 300 may include CV2X subframe n-1 315 and CV2X subframe n
320. Although not explicitly shown, additional subframes may be
present in subframe structure 300.
[0083] Subframe n-1 315 and subframe n 320 may each include 14
symbols. In some examples, the first two symbols of subframe n-1
315 and subframe n 320 may include physical sidelink channels
305-a. Assuming the symbols are numbered zero to thirteen, symbols
two, five, eight, and eleven may include demodulation reference
signals (DMRS). The remaining symbols of subframe n-1 315 and
subframe n 320 may include physical sidelink channels 305-a, except
for the last symbol 310. Symbol 310 may be a guard symbol for each
subframe n-1 315 and subframe n 320 when no CV2X transmissions
occur. It may be in this guard symbol 310 that the estimation
procedure described herein may take place.
[0084] In some cases, a UE may know that CV2X waveforms in symbol
13 in a subframe does not have data (e.g., the subframe is empty of
CV2X transmissions) to allow transmitter-receiver turnaround and
downlink timing adjustments. Since the ITS band may solely be used
for CV2X communications, and all CV2X wireless devices (e.g., UEs)
are synchronized in subframe timing with GPS, a UE may safely
assume that no CV2X signal is present in symbol 13 (e.g., symbol
310). A UE may detect the WIFI interference in symbol 13 (e.g.,
symbol 310) of the subframe (e.g., subframe n-1 315) before the
subframe (e.g., subframe n 320) in which the CV2X signal is decoded
since WIFI is not synchronous with CV2X. For example, a UE may
estimate noise plus WIFI interference during symbol 310-a of
subframe n-1 315 and use the estimate to improve noise plus
interference whitening in subframe n 320. In some cases, a UE may
apply the noise plus interference whitening to more than one
subsequent subframe when the interference (and noise) is within a
threshold of the measurement at symbol 310-a. In some cases, this
estimation and mitigation of interference may occur every subframe.
For example, an estimation may occur at symbol 310-a and applied to
subframe n 320 and an estimation may occur at 310-b to be applied
to subframe n+1, and so on.
[0085] Additionally, a UE may estimate LTE interference on subframe
n. For example, the UE may buffer the first thirteen symbols of a
subframe (e.g., symbols 0 to 12 of subframe n) and then measure and
estimate LTE interference during the fourteenth symbol (e.g.,
symbol 13, symbol 310-b). The UE may then decode the buffered
symbols of subframe n based on the LTE interference measurement at
symbol 310-b. In some examples, the LTE interference estimate at
symbol 310-b may be combined with the noise plus WIFI interference
estimate at symbol 310-a to improve decoding of subframe n 320. In
some cases, the UE may make an additional WIFI plus noise
measurement at symbol 310-b to the measurement at 310-a. These
interference measurements may be used individually or in
combination for the whitening estimation of subframe n. Similarly,
an additional LTE interference measurement may be made at symbol
310-a to be used with the measurement at 310-b, which may be used
individually or in combination for the whitening estimation of
subframe n.
[0086] FIG. 4 illustrates an example of a process flow 400 that
supports inter-radio access technology interference cancellation in
accordance with aspects of the present disclosure. In some
examples, process flow 400 may implement aspects of wireless
communications systems 100 and/or 200. Process flow 400 may include
UE 115-c and UE 115-d, which may be examples UEs 115 as described
herein with reference to FIGS. 1-3.
[0087] In the following description of the process flow 400, the
operations between UE 115-c and UE 115-d may be transmitted in a
different order than the order shown, or the operations performed
by UE 115-c and UE 115-d may be performed in different orders or at
different times. Certain operations may also be left out of the
process flow 400, or other operations may be added to the process
flow 400. It is to be understood that while UE 115-c and UE 115-d
are shown performing a number of the operations of process flow
400, any wireless device may perform the operations shown.
[0088] At 405, UE 115-c may identify, within a first TTI, a symbol
period in which a set of wireless devices operating in accordance
with a CV2X RAT (e.g., UE 115-c and UE 115-d) are configured to
refrain from transmitting. The UE 115-c may, for example, identify
the symbol period as being indicated in a preconfiguration, such as
from a technical specification, for the CV2X RAT. The
preconfiguration may be locally stored in a memory or other storage
device of the UE 115-c. In some examples, the UE 115-c may identify
the symbol period as being indicated in receive control signaling
(e.g., RRC signaling) received from a serving base station that
configures the UE 115-c to refrain from transmitting during the
symbol period.
[0089] At 410, UE 115-c may measure interference of a second RAT
during the symbol period, the second RAT differing from the CV2X
RAT (e.g., a WLAN RAT). In some examples, the symbol period may be
the last symbol of the first TTI (e.g., a subframe of 14 symbols).
Measuring interference at 410 may optionally include generating,
for the symbol period, a plurality of interference measurements
using a plurality of antennas of the UE and generating a covariance
interference metric based on the plurality of interference
measurements, where the CV2X waveform is decoded based on the
covariance interference metric.
[0090] At 415, UE 115-c may optionally measure, for the symbol
period, interference of at least one additional RAT differing from
the CV2X RAT (e.g., an LTE RAT). In some examples, the symbol
period may be the last symbol of the first TTI (e.g., a subframe)
and/or at least a portion of subframe n. Measuring interference at
415 may optionally include generating, for the symbol period, a
plurality of interference measurements using a plurality of
antennas of the UE, and generating a covariance interference metric
based on the plurality of interference measurements, where the CV2X
waveform is decoded based on the covariance interference metric. In
some examples, the covariance interference metric may be based on
the measurements of interference at 410 and 415. For instance, the
covariance interference metric may be based on WLAN interference
and LTE interference.
[0091] At 420, UE 115-d may transmit subframe n to UE 115-c.
Subframe n may occur immediately after the first TTI, which
measurement 410 was taken. In some cases, subframe n may occur
immediately before subframe n+1. Subframe n may include control
signaling (e.g., DMRS) and/or data.
[0092] At 425, UE 115-c may decode a CV2X waveform during the first
TTI or a second TTI based on the measured interference at 410 and
optionally the measured interference of the at least one additional
RAT at 415. In some examples, UE 115-c may apply noise whitening
processing to the CV2X waveform based on the interference
measurement at 410 and optionally the interference measurement at
415.
[0093] At 430, UE 115-d may optionally transmit subframe n+1 to UE
115-c. Subframe n+1 may occur immediately after subframe n.
Subframe n+1 may include control signaling (e.g., DMRS) and/or
data.
[0094] At 435, UE 115-c may optionally decode a CV2X waveform
during a third TTI based on the measured interference at 410 and
optionally the measured interference of the at least one additional
RAT at 415. In some examples, UE 115-c may apply noise whitening
processing to the CV2X waveform based on the interference
measurement from a previous measurement (e.g., taken at 410 and/or
415). In some cases, UE 115-c may optionally measure interference
within a second symbol period (e.g., subframe n), where the CV2X
waveform of subframe n+1 is decoded based on the interference
measured within the second symbol period (e.g., subframe n).
[0095] FIG. 5 shows a block diagram 500 of a device 505 that
supports inter-radio access technology interference cancellation in
accordance with aspects of the present disclosure. The device 505
may be an example of aspects of a UE 115 as described herein. The
device 505 may include a receiver 510, a communications manager
515, and a transmitter 520. The device 505 may also include a
processor. Each of these components may be in communication with
one another (e.g., via one or more buses).
[0096] The receiver 510 may receive information such as packets,
user data, or control information associated with various
information channels (e.g., control channels, data channels, and
information related to inter-radio access technology interference
cancellation, etc.). Information may be passed on to other
components of the device 505. The receiver 510 may be an example of
aspects of the transceiver 820 described with reference to FIG. 8.
The receiver 510 may utilize a single antenna or a set of
antennas.
[0097] The communications manager 515 may identify, within a first
TTI, a symbol period in which a set of wireless devices operating
in accordance with a cellular vehicle to everything (CV2X) RAT are
configured to refrain from transmitting, measure interference of a
second RAT during the symbol period, the second RAT differing from
the CV2X RAT, and decode a CV2X waveform during the first TTI or a
second TTI based on the measured interference. The communications
manager 515 may be an example of aspects of the communications
manager 810 described herein. The actions performed by the
communications manager 515 as described herein may be implemented
to realize one or more potential advantages. One implementation may
allow a UE 115 to save power and reduce interference cancellation
computational complexity by avoiding having to perform interference
measurements when CV2X signals are present. Another implementation
may provide improved quality and reliability of service at the UE
115, as latency and interference at the UE 115 may be reduced.
[0098] The communications manager 515, or its sub-components, may
be implemented in hardware, code (e.g., software or firmware)
executed by a processor, or any combination thereof. If implemented
in code executed by a processor, the functions of the
communications manager 515, or its sub-components may be executed
by a general-purpose processor, a digital signal processor (DSP),
an application-specific integrated circuit (ASIC), a field
programmable gate array (FPGA) or other programmable logic device,
discrete gate or transistor logic, discrete hardware components, or
any combination thereof designed to perform the functions described
in the present disclosure.
[0099] The communications manager 515, or its sub-components, may
be physically located at various positions, including being
distributed such that portions of functions are implemented at
different physical locations by one or more physical components. In
some examples, the communications manager 515, or its
sub-components, may be a separate and distinct component in
accordance with various aspects of the present disclosure. In some
examples, the communications manager 515, or its sub-components,
may be combined with one or more other hardware components,
including but not limited to an input/output (I/O) component, a
transceiver, a network server, another computing device, one or
more other components described in the present disclosure, or a
combination thereof in accordance with various aspects of the
present disclosure.
[0100] The transmitter 520 may transmit signals generated by other
components of the device 505. In some examples, the transmitter 520
may be collocated with a receiver 510 in a transceiver module. For
example, the transmitter 520 may be an example of aspects of the
transceiver 820 described with reference to FIG. 8. The transmitter
520 may utilize a single antenna or a set of antennas.
[0101] FIG. 6 shows a block diagram 600 of a device 605 that
supports inter-radio access technology interference cancellation in
accordance with aspects of the present disclosure. The device 605
may be an example of aspects of a device 505, or a UE 115 as
described herein. The device 605 may include a receiver 610, a
communications manager 615, and a transmitter 635. The device 605
may also include a processor. Each of these components may be in
communication with one another (e.g., via one or more buses).
[0102] The receiver 610 may receive information such as packets,
user data, or control information associated with various
information channels (e.g., control channels, data channels, and
information related to inter-radio access technology interference
cancellation, etc.). Information may be passed on to other
components of the device 605. The receiver 610 may be an example of
aspects of the transceiver 820 described with reference to FIG. 8.
The receiver 610 may utilize a single antenna or a set of
antennas.
[0103] The communications manager 615 may be an example of aspects
of the communications manager 515 as described herein. The
communications manager 615 may include a symbol period identifier
620, an interference detector 625, and a decoder 630. The
communications manager 615 may be an example of aspects of the
communications manager 810 described herein.
[0104] The symbol period identifier 620 may identify, within a
first TTI, a symbol period in which a set of wireless devices
operating in accordance with a cellular vehicle to everything
(CV2X) RAT are configured to refrain from transmitting.
[0105] The interference detector 625 may measure interference of a
second RAT during the symbol period, the second RAT differing from
the CV2X RAT.
[0106] The decoder 630 may decode a CV2X waveform during the first
TTI or a second TTI based on the measured interference.
[0107] The transmitter 635 may transmit signals generated by other
components of the device 605. In some examples, the transmitter 635
may be collocated with a receiver 610 in a transceiver module. For
example, the transmitter 635 may be an example of aspects of the
transceiver 820 described with reference to FIG. 8. The transmitter
635 may utilize a single antenna or a set of antennas.
[0108] Based on reducing computational complexity of interference
cancellation (e.g., whitening), a processor of a UE 115 (e.g.,
controlling the receiver 610, the transmitter 635, or the
transceiver 820 as described with reference to FIG. 8) may
efficiently determine what the interference from non-CV2X RATs is
on CV2X transmissions. Further, the processor of UE 115 may
transmit reduce power consumption due to the reduced computational
complexity. As such, the processor may avoid overheating.
[0109] FIG. 7 shows a block diagram 700 of a communications manager
705 that supports inter-radio access technology interference
cancellation in accordance with aspects of the present disclosure.
The communications manager 705 may be an example of aspects of a
communications manager 515, a communications manager 615, or a
communications manager 810 described herein. The communications
manager 705 may include a symbol period identifier 710, an
interference detector 715, a decoder 720, a transmission manager
725, an interference metric generator 730, a buffer 735, a noise
whitening manager 740, a WLAN interference detector 745, and an LTE
interference detector 750. Each of these modules may communicate,
directly or indirectly, with one another (e.g., via one or more
buses).
[0110] The symbol period identifier 710 may identify, within a
first TTI, a symbol period in which a set of wireless devices
operating in accordance with a cellular vehicle to everything
(CV2X) RAT are configured to refrain from transmitting. In some
examples, the symbol period identifier 710 may identify that the
symbol period is a last symbol period of the first TTI, the first
TTI including a set of symbol periods. In some cases, the first TTI
is a subframe.
[0111] The interference detector 715 may measure interference of a
second RAT during the symbol period, the second RAT differing from
the CV2X RAT. In some examples, the interference detector 715 may
generate, for the symbol period, a set of interference measurements
using a set of antennas of the UE. In some examples, the
interference detector 715 may generate an interference power
measurement for the symbol period, where the CV2X waveform is
decoded based on the interference power measurement. In some
examples, the interference detector 715 may measure, for the symbol
period, interference of at least one additional RAT, where the CV2X
waveform is decoded based on the measured interference of the at
least one additional RAT. In some examples, the interference
detector 715 may measure interference within a second symbol
period, where the CV2X waveform is decoded based on the
interference measured within the second symbol period.
[0112] The decoder 720 may decode a CV2X waveform during the first
TTI or a second TTI based on the measured interference. In some
examples, the decoder 720 may decode the CV2X waveform in the
second TTI that occurs after the first TTI based on the measured
interference. In some examples, the decoder 720 may decode the CV2X
waveform in the first TTI. In some cases, the second TTI occurs
immediately after the first TTI. In some cases, at least one
intervening TTI occurs between the first TTI and the second
TTI.
[0113] The transmission manager 725 may identify a preconfiguration
or receiving control signaling that configures the UE to refrain
from transmitting during the symbol period.
[0114] The interference metric generator 730 may generate a
covariance interference metric based on the set of interference
measurements, where the CV2X waveform is decoded based on the
covariance interference metric. In some examples, the interference
metric generator 730 may generate a noise statistic, an
interference statistic, or both, for the symbol period, where the
CV2X waveform is decoded based on the noise statistic, the
interference statistic, or both.
[0115] The buffer 735 may buffer samples of the CV2X waveform
generated for a set of symbol periods of the first TTI that occur
prior to the symbol period within the first TTI, where the CV2X
waveform is received during the first TTI and decoded based on the
buffered samples.
[0116] The noise whitening manager 740 may apply noise whitening
processing to the CV2X waveform based at least in interference
measurement.
[0117] The WLAN interference detector 745 may measure, during the
symbol period, the interference of a WLAN RAT. The LTE interference
detector 750 may measure, during the symbol period, the
interference of an LTE RAT.
[0118] FIG. 8 shows a diagram of a system 800 including a device
805 that supports inter-radio access technology interference
cancellation in accordance with aspects of the present disclosure.
The device 805 may be an example of or include the components of
device 505, device 605, or a UE 115 as described herein. The device
805 may include components for bi-directional voice and data
communications including components for transmitting and receiving
communications, including a communications manager 810, an I/O
controller 815, a transceiver 820, an antenna 825, memory 830, and
a processor 840. These components may be in electronic
communication via one or more buses (e.g., bus 845).
[0119] The communications manager 810 may identify, within a first
TTI, a symbol period in which a set of wireless devices operating
in accordance with a cellular vehicle to everything (CV2X) RAT are
configured to refrain from transmitting, measure interference of a
second RAT during the symbol period, the second RAT differing from
the CV2X RAT, and decode a CV2X waveform during the first TTI or a
second TTI based on the measured interference.
[0120] The I/O controller 815 may manage input and output signals
for the device 805. The I/O controller 815 may also manage
peripherals not integrated into the device 805. In some cases, the
I/O controller 815 may represent a physical connection or port to
an external peripheral. In some cases, the I/O controller 815 may
utilize an operating system such as iOS.RTM., ANDROID.RTM.,
MS-DOS.RTM., MS-WINDOWS.RTM., OS/2.RTM., UNIX.RTM., LINUX.RTM., or
another known operating system. In other cases, the I/O controller
815 may represent or interact with a modem, a keyboard, a mouse, a
touchscreen, or a similar device. In some cases, the I/O controller
815 may be implemented as part of a processor. In some cases, a
user may interact with the device 805 via the I/O controller 815 or
via hardware components controlled by the I/O controller 815.
[0121] The transceiver 820 may communicate bi-directionally, via
one or more antennas, wired, or wireless links as described herein.
For example, the transceiver 820 may represent a wireless
transceiver and may communicate bi-directionally with another
wireless transceiver. The transceiver 820 may also include a modem
to modulate the packets and provide the modulated packets to the
antennas for transmission, and to demodulate packets received from
the antennas.
[0122] In some cases, the wireless device may include a single
antenna 825. However, in some cases the device may have more than
one antenna 825, which may be capable of concurrently transmitting
or receiving multiple wireless transmissions.
[0123] The memory 830 may include RAM and ROM. The memory 830 may
store computer-readable, computer-executable code 835 including
instructions that, when executed, cause the processor to perform
various functions described herein. In some cases, the memory 830
may contain, among other things, a basic input-output system (BIOS)
which may control basic hardware or software operation such as the
interaction with peripheral components or devices.
[0124] The processor 840 may include an intelligent hardware
device, (e.g., a general-purpose processor, a DSP, a CPU, a
microcontroller, an ASIC, an FPGA, a programmable logic device, a
discrete gate or transistor logic component, a discrete hardware
component, or any combination thereof). In some cases, the
processor 840 may be configured to operate a memory array using a
memory controller. In other cases, a memory controller may be
integrated into the processor 840. The processor 840 may be
configured to execute computer-readable instructions stored in a
memory (e.g., the memory 830) to cause the device 805 to perform
various functions (e.g., functions or tasks supporting inter-radio
access technology interference cancellation).
[0125] The code 835 may include instructions to implement aspects
of the present disclosure, including instructions to support
wireless communications. The code 835 may be stored in a
non-transitory computer-readable medium such as system memory or
other type of memory. In some cases, the code 835 may not be
directly executable by the processor 840 but may cause a computer
(e.g., when compiled and executed) to perform functions described
herein.
[0126] FIG. 9 shows a flowchart illustrating a method 900 that
supports inter-radio access technology interference cancellation in
accordance with aspects of the present disclosure. The operations
of method 900 may be implemented by a UE 115 or its components as
described herein. For example, the operations of method 900 may be
performed by a communications manager as described with reference
to FIGS. 5 through 8. In some examples, a UE may execute a set of
instructions to control the functional elements of the UE to
perform the functions described herein. Additionally or
alternatively, a UE may perform aspects of the functions described
herein using special-purpose hardware.
[0127] At 905, the UE may identify, within a first TTI, a symbol
period in which a set of wireless devices operating in accordance
with a cellular vehicle to everything (CV2X) RAT are configured to
refrain from transmitting. The operations of 905 may be performed
according to the methods described herein. In some examples,
aspects of the operations of 905 may be performed by a symbol
period identifier as described with reference to FIGS. 5 through
8.
[0128] At 910, the UE may measure interference of a second RAT
during the symbol period, the second RAT differing from the CV2X
RAT. The operations of 910 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 910 may be performed by an interference detector as
described with reference to FIGS. 5 through 8.
[0129] At 915, the UE may decode a CV2X waveform during the first
TTI or a second TTI based on the measured interference. The
operations of 915 may be performed according to the methods
described herein. In some examples, aspects of the operations of
915 may be performed by a decoder as described with reference to
FIGS. 5 through 8.
[0130] FIG. 10 shows a flowchart illustrating a method 1000 that
supports inter-radio access technology interference cancellation in
accordance with aspects of the present disclosure. The operations
of method 1000 may be implemented by a UE 115 or its components as
described herein. For example, the operations of method 1000 may be
performed by a communications manager as described with reference
to FIGS. 5 through 8. In some examples, a UE may execute a set of
instructions to control the functional elements of the UE to
perform the functions described herein. Additionally or
alternatively, a UE may perform aspects of the functions described
herein using special-purpose hardware.
[0131] At 1005, the UE may identify, within a first TTI, a symbol
period in which a set of wireless devices operating in accordance
with a cellular vehicle to everything (CV2X) RAT are configured to
refrain from transmitting. The operations of 1005 may be performed
according to the methods described herein. In some examples,
aspects of the operations of 1005 may be performed by a symbol
period identifier as described with reference to FIGS. 5 through
8.
[0132] At 1010, the UE may identify a preconfiguration or receiving
control signaling that configures the UE to refrain from
transmitting during the symbol period. The operations of 1010 may
be performed according to the methods described herein. In some
examples, aspects of the operations of 1010 may be performed by a
transmission manager as described with reference to FIGS. 5 through
8.
[0133] At 1015, the UE may identify that the symbol period is a
last symbol period of the first TTI, the first TTI including a set
of symbol periods. The operations of 1015 may be performed
according to the methods described herein. In some examples,
aspects of the operations of 1015 may be performed by a symbol
period identifier as described with reference to FIGS. 5 through
8.
[0134] At 1020, the UE may measure interference of a second RAT
during the symbol period, the second RAT differing from the CV2X
RAT. The operations of 1020 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 1020 may be performed by an interference detector as
described with reference to FIGS. 5 through 8.
[0135] At 1025, the UE may decode a CV2X waveform during the first
TTI or a second TTI based on the measured interference. The
operations of 1025 may be performed according to the methods
described herein. In some examples, aspects of the operations of
1025 may be performed by a decoder as described with reference to
FIGS. 5 through 8.
[0136] FIG. 11 shows a flowchart illustrating a method 1100 that
supports inter-radio access technology interference cancellation in
accordance with aspects of the present disclosure. The operations
of method 1100 may be implemented by a UE 115 or its components as
described herein. For example, the operations of method 1100 may be
performed by a communications manager as described with reference
to FIGS. 5 through 8. In some examples, a UE may execute a set of
instructions to control the functional elements of the UE to
perform the functions described herein. Additionally or
alternatively, a UE may perform aspects of the functions described
herein using special-purpose hardware.
[0137] At 1105, the UE may identify, within a first TTI, a symbol
period in which a set of wireless devices operating in accordance
with a cellular vehicle to everything (CV2X) RAT are configured to
refrain from transmitting. The operations of 1105 may be performed
according to the methods described herein. In some examples,
aspects of the operations of 1105 may be performed by a symbol
period identifier as described with reference to FIGS. 5 through
8.
[0138] At 1110, the UE may measure interference of a second RAT
during the symbol period, the second RAT differing from the CV2X
RAT. The operations of 1110 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 1110 may be performed by an interference detector as
described with reference to FIGS. 5 through 8.
[0139] At 1115, the UE may generate, for the symbol period, a set
of interference measurements using a set of antennas of the UE. The
operations of 1115 may be performed according to the methods
described herein. In some examples, aspects of the operations of
1115 may be performed by an interference detector as described with
reference to FIGS. 5 through 8.
[0140] At 1120, the UE may generate a covariance interference
metric based on the set of interference measurements, where the
CV2X waveform is decoded based on the covariance interference
metric. The operations of 1120 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 1120 may be performed by an interference metric
generator as described with reference to FIGS. 5 through 8.
[0141] At 1125, the UE may decode a CV2X waveform during the first
TTI or a second TTI based on the measured interference. The
operations of 1125 may be performed according to the methods
described herein. In some examples, aspects of the operations of
1125 may be performed by a decoder as described with reference to
FIGS. 5 through 8.
[0142] FIG. 12 shows a flowchart illustrating a method 1200 that
supports inter-radio access technology interference cancellation in
accordance with aspects of the present disclosure. The operations
of method 1200 may be implemented by a UE 115 or its components as
described herein. For example, the operations of method 1200 may be
performed by a communications manager as described with reference
to FIGS. 5 through 8. In some examples, a UE may execute a set of
instructions to control the functional elements of the UE to
perform the functions described herein. Additionally or
alternatively, a UE may perform aspects of the functions described
herein using special-purpose hardware.
[0143] At 1205, the UE may identify, within a first TTI, a symbol
period in which a set of wireless devices operating in accordance
with a cellular vehicle to everything (CV2X) RAT are configured to
refrain from transmitting. The operations of 1205 may be performed
according to the methods described herein. In some examples,
aspects of the operations of 1205 may be performed by a symbol
period identifier as described with reference to FIGS. 5 through
8.
[0144] At 1210, the UE may measure interference of a second RAT
during the symbol period, the second RAT differing from the CV2X
RAT. The operations of 1210 may be performed according to the
methods described herein. In some examples, aspects of the
operations of 1210 may be performed by an interference detector as
described with reference to FIGS. 5 through 8.
[0145] At 1215, the UE may measure, for the symbol period,
interference of at least one additional RAT, where the CV2X
waveform is decoded based on the measured interference of the at
least one additional RAT. The operations of 1215 may be performed
according to the methods described herein. In some examples,
aspects of the operations of 1215 may be performed by an
interference detector as described with reference to FIGS. 5
through 8.
[0146] At 1220, the UE may apply noise whitening processing to the
CV2X waveform based at least in interference measurement. The
operations of 1220 may be performed according to the methods
described herein. In some examples, aspects of the operations of
1220 may be performed by a noise whitening manager as described
with reference to FIGS. 5 through 8.
[0147] At 1225, the UE may decode a CV2X waveform during the first
TTI or a second TTI based on the measured interference. The
operations of 1225 may be performed according to the methods
described herein. In some examples, aspects of the operations of
1225 may be performed by a decoder as described with reference to
FIGS. 5 through 8.
[0148] It should be noted that the methods described herein
describe possible implementations, and that the operations and the
steps may be rearranged or otherwise modified and that other
implementations are possible. Further, aspects from two or more of
the methods may be combined.
[0149] Techniques described herein may be used for various wireless
communications systems such as code division multiple access
(CDMA), time division multiple access (TDMA), frequency division
multiple access (FDMA), orthogonal frequency division multiple
access (OFDMA), single carrier frequency division multiple access
(SC-FDMA), and other systems. A CDMA system may implement a radio
technology such as CDMA2000, Universal Terrestrial Radio Access
(UTRA), etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards.
IS-2000 Releases may be commonly referred to as CDMA2000 1.times.,
1.times., etc. IS-856 (TIA-856) is commonly referred to as CDMA2000
1.times.EV-DO, High Rate Packet Data (HRPD), etc. UTRA includes
Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may
implement a radio technology such as Global System for Mobile
Communications (GSM).
[0150] An OFDMA system may implement a radio technology such as
Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), Institute of
Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE
802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are
part of Universal Mobile Telecommunications System (UMTS). LTE,
LTE-A, and LTE-A Pro are releases of UMTS that use E-UTRA. UTRA,
E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in
documents from the organization named "3rd Generation Partnership
Project" (3GPP). CDMA2000 and UMB are described in documents from
an organization named "3rd Generation Partnership Project 2"
(3GPP2). The techniques described herein may be used for the
systems and radio technologies mentioned herein as well as other
systems and radio technologies. While aspects of an LTE, LTE-A,
LTE-A Pro, or NR system may be described for purposes of example,
and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of
the description, the techniques described herein are applicable
beyond LTE, LTE-A, LTE-A Pro, or NR applications.
[0151] A macro cell generally covers a relatively large geographic
area (e.g., several kilometers in radius) and may allow
unrestricted access by UEs with service subscriptions with the
network provider. A small cell may be associated with a
lower-powered base station, as compared with a macro cell, and a
small cell may operate in the same or different (e.g., licensed,
unlicensed, etc.) frequency bands as macro cells. Small cells may
include pico cells, femto cells, and micro cells according to
various examples. A pico cell, for example, may cover a small
geographic area and may allow unrestricted access by UEs with
service subscriptions with the network provider. A femto cell may
also cover a small geographic area (e.g., a home) and may provide
restricted access by UEs having an association with the femto cell
(e.g., UEs in a closed subscriber group (CSG), UEs for users in the
home, and the like). An eNB for a macro cell may be referred to as
a macro eNB. An eNB for a small cell may be referred to as a small
cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may
support one or multiple (e.g., two, three, four, and the like)
cells, and may also support communications using one or multiple
component carriers.
[0152] The wireless communications systems described herein may
support synchronous or asynchronous operation. For synchronous
operation, the base stations may have similar frame timing, and
transmissions from different base stations may be approximately
aligned in time. For asynchronous operation, the base stations may
have different frame timing, and transmissions from different base
stations may not be aligned in time. The techniques described
herein may be used for either synchronous or asynchronous
operations.
[0153] Information and signals described herein may be represented
using any of a variety of different technologies and techniques.
For example, data, instructions, commands, information, signals,
bits, symbols, and chips that may be referenced throughout the
description may be represented by voltages, currents,
electromagnetic waves, magnetic fields or particles, optical fields
or particles, or any combination thereof.
[0154] The various illustrative blocks and modules described in
connection with the disclosure herein may be implemented or
performed with a general-purpose processor, a DSP, an ASIC, an
FPGA, or other programmable logic device, discrete gate or
transistor logic, discrete hardware components, or any combination
thereof designed to perform the functions described herein. A
general-purpose processor may be a microprocessor, but in the
alternative, the processor may be any conventional processor,
controller, microcontroller, or state machine. A processor may also
be implemented as a combination of computing devices (e.g., a
combination of a DSP and a microprocessor, multiple
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration).
[0155] The functions described herein may be implemented in
hardware, software executed by a processor, firmware, or any
combination thereof. If implemented in software executed by a
processor, the functions may be stored on or transmitted over as
one or more instructions or code on a computer-readable medium.
Other examples and implementations are within the scope of the
disclosure and appended claims. For example, due to the nature of
software, functions described herein can be implemented using
software executed by a processor, hardware, firmware, hardwiring,
or combinations of any of these. Features implementing functions
may also be physically located at various positions, including
being distributed such that portions of functions are implemented
at different physical locations.
[0156] Computer-readable media includes both non-transitory
computer storage media and communication media including any medium
that facilitates transfer of a computer program from one place to
another. A non-transitory storage medium may be any available
medium that can be accessed by a general purpose or special purpose
computer. By way of example, and not limitation, non-transitory
computer-readable media may include random-access memory (RAM),
read-only memory (ROM), electrically erasable programmable ROM
(EEPROM), flash memory, compact disk (CD) ROM or other optical disk
storage, magnetic disk storage or other magnetic storage devices,
or any other non-transitory medium that can be used to carry or
store desired program code means in the form of instructions or
data structures and that can be accessed by a general-purpose or
special-purpose computer, or a general-purpose or special-purpose
processor. Also, any connection is properly termed a
computer-readable medium. For example, if the software is
transmitted from a website, server, or other remote source using a
coaxial cable, fiber optic cable, twisted pair, digital subscriber
line (DSL), or wireless technologies such as infrared, radio, and
microwave, then the coaxial cable, fiber optic cable, twisted pair,
DSL, or wireless technologies such as infrared, radio, and
microwave are included in the definition of medium. Disk and disc,
as used herein, include CD, laser disc, optical disc, digital
versatile disc (DVD), floppy disk and Blu-ray disc where disks
usually reproduce data magnetically, while discs reproduce data
optically with lasers. Combinations of the above are also included
within the scope of computer-readable media.
[0157] As used herein, including in the claims, "or" as used in a
list of items (e.g., a list of items prefaced by a phrase such as
"at least one of" or "one or more of") indicates an inclusive list
such that, for example, a list of at least one of A, B, or C means
A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also,
as used herein, the phrase "based on" shall not be construed as a
reference to a closed set of conditions. For example, an exemplary
step that is described as "based on condition A" may be based on
both a condition A and a condition B without departing from the
scope of the present disclosure. In other words, as used herein,
the phrase "based on" shall be construed in the same manner as the
phrase "based at least in part on."
[0158] In the appended figures, similar components or features may
have the same reference label. Further, various components of the
same type may be distinguished by following the reference label by
a dash and a second label that distinguishes among the similar
components. If just the first reference label is used in the
specification, the description is applicable to any one of the
similar components having the same first reference label
irrespective of the second reference label, or other subsequent
reference label.
[0159] The description set forth herein, in connection with the
appended drawings, describes example configurations and does not
represent all the examples that may be implemented or that are
within the scope of the claims. The term "exemplary" used herein
means "serving as an example, instance, or illustration," and not
"preferred" or "advantageous over other examples." The detailed
description includes specific details for the purpose of providing
an understanding of the described techniques. These techniques,
however, may be practiced without these specific details. In some
instances, well-known structures and devices are shown in block
diagram form in order to avoid obscuring the concepts of the
described examples.
[0160] The description herein is provided to enable a person
skilled in the art to make or use the disclosure. Various
modifications to the disclosure will be readily apparent to those
skilled in the art, and the generic principles defined herein may
be applied to other variations without departing from the scope of
the disclosure. Thus, the disclosure is not limited to the examples
and designs described herein but is to be accorded the broadest
scope consistent with the principles and novel features disclosed
herein.
* * * * *